The invention is related to the field of imaging using a system of dispersive and other optical elements to achieve a plane of high photon flux necessary for nonlinear optical processes to occur. This plane may be positioned at will along the optical axis through controlling the amount of dispersion in the beam. The illumination at the plane can be controlled to give uniform illumination and structured illumination for better contrast, rejection of background signal, and axial resolution. The invention is applicable to microscopes as well as endoscopes, and in particular a high sensitivity temporal focusing wide field multiphoton endoscope capable of deep imaging.
Traditional histological analysis is the clinical gold standard for cancer diagnosis but requires tissues to be excised, fixed, sectioned, stained and subsequently examined microscopically. Endoscopes allow for optical examination of tissues within the body cavity and complements traditional histological analysis of diseases. In certain cases, such as cancers occurring in the bronchial tree, excisional biopsy should be minimized and optical biopsy via endoscopy has the potential to guide excisional biopsy and to partly replace them. Moreover, optical biopsy is a powerful tool to determine the surgical margins during resection of cancerous lesions. Furthermore, nonlinear optical processes such as second-harmonic generation (SHG) are useful in examining extracellular matrix structures non-invasively. Studies have demonstrated its utility in the diagnosis of muscular dystrophy and in the diagnosis of ovarian cancer. Recent studies have demonstrated that it is possible to quantify the correlation between abnormally increased collagen fiber content fibrosis progression using optical means such as SHG.